Structural Phase Stability Studies on MBeH3 (M = Li, Na, K, Rb, Cs) from Density Functional Calculations

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• 作者：P. Vajeeston ; P. Ravindran ; H. Fjellv&aring ; g
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：January 21, 2008
• 年：2008
• 卷：47
• 期：2
• 页码：508 - 514
• 全文大小：242K
• 年卷期：v.47,no.2(January 21, 2008)
• ISSN：1520-510X

文摘

Density functional theory calculations within the generalized-gradient approximation are used to establish the ground-state structure, equilibrium structural parameters, and electronic structure for MBeH₃ phases. From the 24 structuralarrangements used as inputs for structural optimization calculations, the ground-state crystal structures of MBeH₃phases have been predicted. At ambient conditions, LiBeH₃ and NaBeH₃ crystallize with perovskite-relatedorthorhombic and cubic structures, respectively. The remaining phases KBeH₃, RbBeH₃, and CsBeH₃ crystalize ina monoclinic structure. In the predicted phases one can store up to 15.93 wt % of hydrogen. The formation energyfor the MBeH₃ phases have been investigated along different reaction pathways. The electronic structures revealthat all these phases are insulators with estimated band gaps varying between 1.79 and 3.44 eV.